Medicine Which of the following is not a component of classical triad of ECG changes in pericardial effusion with cardiac tamponade? A Sinus tachycardia B Prolonged ST segment C Low voltage QRS complex D Electrical alternans 💡 Explanation Which of the following is not a component of classical triad of ECG changes in pericardial effusion with cardiac tamponade? ✓ Correct Answer: B. Prolonged ST segment